Surfacing apparatus



v Dec.f23, 1930. HQ R. STRATFORD l,786,320

SURFACING APPARATUS original Filed oct. 10. 1927 JNVENTOR.

jaw# ff @afg/fwd ATTORNEYS.

iPatented Dec. 1930 i UNITED STATES PATENT OFFICE HERBERT R. STBATFOBD, F CLEVELAND, OHIO, ASSIGNOR TO THE STRATMORE COM- OF CLEVELAND, OHIO, .A CORPORATION OF OHIO SURFACING APPARATUS Application filed October 10, 1927, Serial No. 225,165. 'Renewed Hay 24, 1930.

The present invention relating, as indicated, to a method of and apparatus for surfacing, is more particularly directed to a new and improved method and apparatus for the abrading of various t pes of surfaces, such for example as pane s and articles of wood, metal and various compositions. rlhe principal object of the invention is the provision of method and means for rapidly cutting down or smoothing surfaces of the character referred to by power and by means of relatively thin. semifiexible abrasive disks.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said' annexed drawing Fig. 1 is a sideelevation of one form of '25 my improved apparatus adapted to carry out y the present improved method; Fig. 2 is a side elevation showing such apparatus in operation; Fig. 3 is a section on the line 3 3, Fig. 1; Fig. 4 is a transverse section through the abrasive disk employed with the a paratus; and Fig. 5 is a modified form o the apparatus illustrated in Figs. 1 and 2.

Referring now to Figs. 1 and 2, the apparatus is seen to consist of a casing 1 provided with handles 2 and 3, the handle 3 also serving as a support and the means for introducing to the interior of the casing a flexible operating shaft 4 which may be led to any suitable source of power, such for example as a portable electric motor which is not shown. The shaft 4 operates suitable gearing in the casin which in turn operates an outwardly exten 'ng shaft 5, to the lower end of which is secured a hub in the form of one or more supporting plates 6 and 7. To

the lower surface of the plate 6 is secured a relatively thin flexible metal supporting disk 8 which is ixeclly mounted with respect to the shaft 5 and is adapted to receive and'support the surfacing disk 9 which is removably 50- secured to the shaft and to the disk 8 at the center of the latter by means of a threaded bolt 10 carrying a slotted head 11. The general construction of the operating mechanism described above is similar to that shown 1n several of my prior pending applications, such for example as Serial No. 101,450, led April 12, 1926. The supporting disk 8 is of highly resistant flexible metal, such for example as tempered steel, or equivalent material, and is intended to resist iiexure under pressure imposed transversely to its normal plane but to yield under such pressure sufficiently to adapt itself to the ordinary contours of the articles on which it is to be used. The surfacing -disk consists of a layer 12 of a suitable paper stock having considerable stiffness and strength, a layer 13 of fabric adhesively secured to one surface of the paper disk, and a layer of abrasive grains 14 adhesivelysecured to the free surface of the cloth 13.` This composite disk is relatively stiff but issuiiciently flexible to adapt itself to the ordinary contours of the articles on which it isused, and the particular function. ofthe supporting disk described above is to reinforce the surfacing disk while permitting the same lexure in the abrasive disk that it would otherwise have for the purpose of accommodating itself to irregular c0ntours. The above described action is facilitated by the non-engaged relationship between the disks 8 and 9vwhich are, as described, only secured together at their central portions by means of the threaded bolt 10 which presses such portions against the bottom side of the disk or'plate 6.

In operation the machine is carried to the surface to be operated upon, the mechanism is operated rotating the shaft 5 at relatively l high speed, and the radially outer portion of the surfacing disk is then pressed against the work in the manner indicated in Fig. 2. This pressure produces a flexing in both the abrasive and supporting disk, allowing all of the surface of the abrasive disk, except the radially outer portion on one side, to remain out of contact with the work and permitting also very accurate control of the operation by the operator.

Under certain conditions the disk 8 may be formed with its radially outer portion lying in a plane at an angle to the main cent-ral portion which will thus permit the supporting and surfacing disks to stand away from each other except over that portion which is pressed against the work, thus increasing the` cooling effect and preventing disintegration or softening of the adhesive employed by reason of the heat generated in the action of the surfacing disk on the work. For most purposes, however, the two disks cool themselves entirely sufficiently merely by theirr rapid rotation in the air.

rlhe present method and apparatus are particularly adapted for intermittent operation where projections must be ground ofi' from various surfaces such as castings, metal panels to be employed in motor car bodies and the like, where certain capacity to flex and conform to the contour of the surface is required but where no local compressibility behind the operatingpportion of the surfacing disk is required. At the speeds employed which are in many cases as high as 4000 to 5000 revolutions per minute, with a disk of nine inches diameter, the centrifugal force acting to maintain the supporting disk in its normal plane greatly increases the resistance to iexure of this element and increases the relative rigidity of it as a support, While its character still permits such flexing as is required for the operations referred to.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the means and the steps herein disclosed, provided those stated by any of the following claims or their equivalent be employed.

I therefore particularly point out and distinctly claim as my invention l. In surfacing apparatus, the combination of a rotatable shaft, a relatively thin flexible lexure resistant disc rigidly secured at its central portion to saidshaft, and a surfacing disc also secured to said shaft, said first disc being free from said surfacing disc except at their respective centers but engaging and resistantly supporting said surfacing disc when pressed against a work surface.

2. In surfacing apparatus, the combination of a rotatable shaft, a relatively thin flexible flexure resistant disc rigidly secured at its central portion to said shaft, and a sur- Signed by me, this 7th day of October, 1927.

HERBERT R. STRATFORD. 

